1. Field of the Invention
This invention relates to a strainer for use in high pressure gas pipelines. The strainer provides a means for removing debris, such as welding slag, from the gas flow. The pipeline strainer permits of the collection of said debris and subsequent removal thereof.
2. Prior Art
There exists a number of commercial pipeline strainers in use, the two most pertinent of which are described herein and illustrated schematically in FIGS. 1(a) and 1(b).
The version shown in FIG. 1(a) comprises a perforated cylindrical basket a, closed at its downstream end, mounted vertically within a cylindrical shell b. The gas is introduced axially into the basket a through an inlet pipe c and then changes direction and passes through the perforations d into the annular space e between the basket and the shell. The debris is thus screened out of the flow and retained inside the basket, whilst the gas turns through the perforations and exits through an outlet conduit f into the pipeline (not shown).
The second pipeline strainer of interest is shown in FIG. 1(b). The strainer comprises a cylindrical shell p, inside which is mounted a transverse, perforated, flat plate q. The debris is screened from the flow by the plate q and drops into a collection sump r, from which it may be removed.
The primary disadvantage of these prior art devices lies in the substantial pressure drop across the complete strainer unit under operating conditions. This pressure drop can be as high as ten p.s.i. Having such a significant pressure drop is undesirable, because it increases the cost of subsequent re-compression of the gas.
In addition, these strainers are relatively expensive to build, due to their configuration.
There is therefore a need for a strainer characterized by a relatively low pressure drop and having a configuration or structure which lends itself to a relatively low manufacturing cost.